Wire coating machine



Feb. 6, 1934.

O. F. FREELAND WIRE coATING MACHINE 2 Sheet's-Sheet 1 Filed Nov. 8e 1930NM.. A

Il, LiNW Feb. 6, 1934. Q F, FREELAND v 1,945,851

WIRE COATING MACHINE Filed Nov. 8, 1.930 2 Sheets-Sheet 2 INVENTOR I umjaw/JM Patented Feb. 6, 1934 UNITED STATES WIRE coA'rrNG MACHINE OrvilleF. Freeland, Muskegon, Mich., assignor to Anaconda Wire and CableCompany, New York, N. Y.,'a corporation of Delaware Application November8, 1930. Serial No. 494,268

6 Claims.

This invention relates to machines adapted for coating electricconductor wire with insulating material such as insulating varnish orenamel. It has heretofore been the practice to coat or l enamel wire bypassing it through a Suitable bath, the Wire being dried by exposure toheat radiated from a suitable heating element such as an electric, oilheater or gas burner. Heretofore drying or baking of insulated coatingshas been ununiform due to changes in temperature conditions in the roomor by changes in outside atmospheric conditions. Where the coatingmaterial such as enamel or varnish is dried or baked by subjecting thecoated wire to radiant heat there is a tendency to bake the enamelharder on the side next to the source of heat.

'Ihe present invention aims to provide means whereby there will be nounevenness in the thickness of the coating as heretofore caused byvariations in atmospheric conditions and also to provide means wherebythe wire treated will have a coating of uniform thickness throughout itslength.

In the embodiment of the invention described, the enamel or similarcoating material is dried or hardened by convection currents of airwhich are caused to surround the entire surface of coated wire and thusequalize the temperature throughout the entire surface. I also providemeans for preheating the air which dries the coating. This preheated airis preferably forced under pressure through an elongated oven or heatingchamber. In this way, I carry on the drying or baking operation under aslight positive pressure so that there can be no infiltration ofatmospheric air from the room in which the apparatus is located. Thus Iavoid variations in the hardness due to changes in room temperature orchanges in outside atmospheric conditions.

It is of utmost importance in the manufacture of enameled wire to supplywire in which the coating material is of uniform thickness, texture,hardness and appearance throughout. By such uniformity of coating, theinsulating value will be the same for al1 parts of the wire, hence noone part will be more apt to fail in practice than any other part. Itfis important to have uni- ,formity of hardness and color. Hardnessdeter- 0 mines the resistance of the coating to abrasion d' by differentconvolutions coming in contact with one another, for example, when thewire is wound to form.magnets or the like. Uniformity of color isimportant because the sale value depends some- 55 what upon thisuniformity of appearance. The

requirements referred to present problems which my invention solves.

The invention will be fully apparent from the following specificationwhen read in connection with the accompanying drawings and will bedefined with particularity in the appended claims. In the drawings, Fig.1 is a longitudinal vertical section through an apparatus embodying theinvention;

Fig. 2 is a horizontal section on line 2-2 of Fig. 1;

Fig. 3 is a transverse 3 3 of Fig. l;

Fig.-4 is a detail plan view of a heating chamber shown in Fig. 1.

Referring in detail to the drawings, 10 and 12 are tanks located atopposite ends of the apparatus, each tank being adapted to contain abody of liquid insulating material such as insulating varnish, enamel orthe like. The tank 10 has rotatably mounted therein a plurality ofrollers 14, 16, 18 and 20. 'Ihe tank 12 has similarl rollers 22, 24, 26and 28 mounted therein. The wire to be coated indicated at W passesunder rollers 14 and 16 and over roller 18; thence through an ovenchamber 30 over roller 22 in a tank 12 under roller 24; then through theoven chamber over roller 16 in tank 10 and around roller 20, thenthrough the oven chamber 30 again; then over roller 26 in tank 12 andaround roller 28; then again through the oven chamber 30. The end of thewire leaving the oven chamber passes around a guide roller 32. Theseveral rollers 14, 16. 18, 20, 22, 24, 26 and 28 all dip into theenamel bath. Thus, each time the wire passes through the oven, itreceives and has baked thereon a coat of insulating material. p

In the embodiment ofthe invention illustrated, in .passage through theoven 30, the wire has four coats baked thereon. During its passagethrough the oven chamber 30, the wire is subjected to the heat ofconvection currents of air. This air is forced by a blower 34 throughpipes 36, 38 and 40 to inlet pipes 42 and 44 which communicateA with theopposite ends of a heating chamber 46.-. At the center, this chambercommunicates by means of ducts 48 with the central vertical section online zone of the oven 30. The air forced to the heati flow in acircuitous path from the inlet pipes 42 preferably enclosed in a casing56 which is provided with a layer of heat insulating material indicatedat 58.

The supply pipe for the gas burner 50 enters through an opening 60 inthe casing which also serves to admit air to support combustion in thefuel supplied to the gas burner.

The products of combustionfrom the burner 50, the heated air from theoven 30 and fumes arising from'the tanks 10 and 12 are adapted to bepassed out to atmosphere through vent pipes 62 and 64. The vent pipe 62is provided with one, hood portion 66 which receives the outgoing airfrom the oven chamber 30. Another hood portion 68 overlies the tank 10.The air which is forced out under pressure through the hood portion 66creates sort of a draft or suction which tends to exhaust the fumesarising from the bath in the tank 10. These fumes pass out through thehood portion 68. The draft created Will also carry off the products ofcombustion from the burner 50. These outgoing hot products serve also tokeep the bath in the tank at the proper temperature. The vent pipe 64may be provided with substantially the same hood arrangement as shown onthe pipe 62 or in some cases it may have .a single substantiallysemicircular hood as shown at '70. l

In operation, usually a great number of bare wires are fed through theoven at the same time. Sometimes as many as 50 wires are passed throughthe apparatus alongside of one another.

The description refers merely to one wire, butr it will be understoodthat a number of wires treated at a given time is dependent only uponthe proper proportioning of' the apparatus. While we have shownapparatus for applying four separate coats to a single wire, theapparatus being adapted for drying each coat, it will be understood thatthe number of coats may be varied at'will depending upon the particularuse to which the Wire is to be put in service. With the apparatusdescribed, it will be clear that the power driven blower suppliespreheated air under Apressure to the oven chamber. Thus there is alwaysa positive pressure maintained therein. This pressure prevents theinfiltration of atmospheric air which would tend to vary the temperaturewithin the oven and thus cause uneven drying., The convection currentsof air apply a uniform heat to all sides of the wire and thus avoid aformation of hard zones such as produced by the old apparatus whereinthe product is heated by radiation.

While I have described quite specifically the particular embodiment ofthe invention herein illustrated it is not to be construed that I amlimited thereto since Various modifications and substitution ofequivalents may be made by those skilled in the art without departingfrom the in vention as defined in the appended claims.

1. In a wire enameling machine, a drying oven comprising a substantiallyhorizontal oven open at both ends, air exhaust ducts positioned adjacenteach open end, means to force preheated air substantially free fromproducts of combustion into the central portion of said oven and baiilemeans to distribute the said air through the oven and to the said airexhaust ducts.

2. In a wire enameling machine, a drying oven comprising a substantiallyhorizontal oven chamber open at both ends, air exhaust ducts positionedadjacent each open end, a heat exchange device having a heated chamberand an adjacent but separate heat exchange chamber, an air inlet and anair outlet in said heat exchange chamber, the said .air outlet openinginto the central portion of the said oven, means to generate heat insaid heated chamber and means to force air into and through said heatexchange chamber into the said oven and baille means to distribute saidair through the oven to the s aid air exhaust ducts.

4. A wire enameling machine comprising a substantially horizontal dryingoven open at both ends, air exhaust ducts positioned adjacent each end,enameling tanks located adjacent each open end, means to pass wire intosaid tanks and through the oven, means to force preheated airsubstantially free from products of combustion into the central portionof said oven and bale means to distribute the said air to the said airexhaust ducts.

5. A wire enameling machine comprising a substantial horizontal dryingoven open at both ends, enameling tanks positioned adjacent said ends,means to pass wire into said tanks and through the oven, air exhaustducts adjacent each open end, an air inlet duct positioned in thecentral portion of the said oven, bailie means to distribute airentering through said inlet to each end of the said oven, means to forcesubstantially pure air through said inlet, and means to preheat saidair, said means including a heat exchange device adapted to preheat saidair Without admixing therewith gaseous products of combustion. V

6. 'I'he method of drying enamel, varnishes and the like insulatingmaterials on coated wires which comprises passing thereover a strongfree iiow of preheated air substantially free from gaseous products ofcombustion.

. ORVILLE F. FREELAND.

